Enzyme-catalyzed condensation reaction in a mammalian alpha-amylase. High-resolution structural analysis of an enzyme-inhibitor complex. |
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| Authors: | M Qian V Nahoum J Bonicel H Bischoff B Henrissat F Payan |
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| Institution: | Architecture et Fonction des Macromolécules Biologiques, UMR 6098, CNRS and Universities Aix-Marseille I and II, 31 Chemin Joseph Aiguier, 13402 Marseille, France. |
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| Abstract: | Mammalian alpha-amylases catalyze the hydrolysis of alpha-linked glucose polymers according to a complex processive mechanism. We have determined the X-ray structures of porcine pancreatic alpha-amylase complexes with the smallest molecule of the trestatin family (acarviosine-glucose) which inhibits porcine pancreatic alpha-amylase and yet is not hydrolyzed by the enzyme. A structure analysis at 1.38 A resolution of this complex allowed for a clear identification of a genuine single hexasaccharide species composed of two alpha-1,4-linked original molecules bound to the active site of the enzyme. The structural results supported by mass spectrometry experiments provide evidence for an enzymatically catalyzed condensation reaction in the crystal. |
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